Cyril Sadowsky

Long-term stability of dental relationships after orthodontic treatment.

Adult changes in selected occlusal parameters are measured, with the study sample limited to 72 subjects with a history of malocclusion treated orthodontically 12 to 35 years previously. Variations were large. Most of the corrections were retained, with mean changes tending toward pretreatment values.

Long-term stability after orthodontic treatment: nonextraction with prolonged retention.

A sample of 22 previously treated orthodontic cases was studied to evaluate long-term stability. All cases were treated nonextraction with fixed edgewise appliances and were without retainers a minimum of 5 years. Data were obtained from study models, although 14 of the 22 cases had longitudinal cephalometric radiographs. The average retention time with a mandibular fixed lingual retainer was 8.4 years. The irregularity index pretreatment was 8.0 mm in the maxillary arch and 5.2 mm in the mandibular arch; at the end of treatment it was 0.9 mm and 1.0 mm, respectively, and at the postretention stage it was 2.0 mm and 2.4 mm, respectively. Resolution of the lower irregularity index was accomplished without incisor advancement or distal movement of the mandibular molar, however, both arches were expanded transversely. During the posttreatment stage all variables showed relapse except for the expanded maxillary canines and premolars. However, the mandibular anterior segment demonstrated relatively good alignment at the long-term stage, which may be a reflection of prolonged mandibular retention.

Long-term assessment of orthodontic relapse

The long-term stability of orthodontic treatment was evaluated in a group of ninety-six former patients who were treated between 12 and 35 years previously. Dental relationships were recorded on study models taken prior to orthodontic treatment, at the end of active treatment, and at long-term follow-up. A malocclusion score was developed for this study, and the over-all static occlusal relationships were categorized by defining an ideal range for eleven variables. Ninety of the ninety-six cases were within the ideal range at the end of treatment. Most of the cases showed an improvement of their malocclusions in the long-term stage. However, of the ninety-six subjects, sixty-nine (72 percent) had at least one variable outside our ideal range in the long-term follow-up. A moderately increased overjet and overbite was responsible in most instances for the result being outside the ideal range in the long term. The long-term result as compared to the original malocclusion exhibited increased overbite in 16 percent of the cases, increased mandibular anterior crowding in 9 percent of the cases, and increased overjet in 5 percent of the cases. The range of ideal, considering only the variables used in this study, will to some extent vary with the eye of the beholder. Therefore, the results of this study need to be interpreted accordingly. It is suggested that orthodontists be well aware of long-term changes in dental relationships many years after treatment and take this into account when advising patients as to the potential benefits of orthodontic treatment.

Prevalence and severity of apical root resorption and alveolar bone loss in orthodontically treated adults

This study assessed the frequency of root resorption and alveolar bone loss in 88 adults who had undergone orthodontic treatment. Pretreatment and posttreatment periapical radiographs were used to determine the amount of external apical root resorption and alveolar bone loss of the maxillary and mandibular incisors. Alveolar bone loss in the posterior quadrants was determined from bite-wing radiographs. The number of incisors showing root resorption, including blunting, increased from 15% before treatment to 73% after treatment. The number of incisors having moderate to severe apical root resorption was 2% before treatment and 24.5% after treatment. The number of anterior sites in which loss of alveolar bone height exceeded 2 mm from the cementoenamel junction to the alveolar crest increased from 19% before treatment to 37% after treatment; the number of posterior sites was 7% before treatment and 14% after treatment. Bone LOSS > or = 1.5 mm from the pretreatment to posttreatment stages occurred in 11% of the incisors and 3% of the posterior sites. A marked increase in the prevalence of root resorption and alveolar bone loss occurred over the course of treatment. The prevalence of iatrogenic effects for adults may be higher for incisors than in previously reported adolescent studies. A small subgroup with multiple sites of either root resorption or bone loss account for a disproportionate number of iatrogenic sequelae. However, in general, the iatrogenic experience did not preclude the orthodontic treatment of adults.

Long-term effects of orthodontic treatment on periodontal health.

The periodontal health of a group of ninety-six patients who had received comprehensive fixed-appliance orthodontic treatment during adolescence between 12 and 35 years previously was evaluated. Comparisons were made with a group of 103 adults who were similar with regard to race, sex, age, socioeconomic status, dental awareness, and oral hygiene status but had malocclusions that had not been orthodontically treated. There were no statistically significant differences in the general prevalence of periodontal disease between the two groups. However, more detailed analysis revealed that the orthodontic group had a greater prevalence of mild to moderate periodontal disease in the maxillary posterior and mandibular anterior regions of the mouth, as compared to the control group. The results suggested that orthodontic treatment in adolescence is not a major factor in determining the long-term periodontal health status. No significant amount of either damage or benefit to the periodontal structures could be directly attributed to orthodontic therapy. Conversely, the lack of orthodontic therapy in adolescence does not appear to influence subsequent development or nondevelopment of periodontal disease in adults.

Mandibular skeletal and dental asymmetry in Class II subdivision malocclusions

Mandibular symmetry was compared between a group of 28 subjects exhibiting Class II subdivision malocclusions and 30 subjects with Class I malocclusions who served as the control group. With submentovertex radiographs, symmetry was assessed by measuring the relative difference in spatial position of mandibular landmarks in both anteroposterior and transverse dimensions as determined by coordinate systems representing the cranial floor, mandible, and mandibular dentition. Only those variables representing the anteroposterior difference between right and left mandibular molar positions showed a statistically significant difference between the groups. Whether the position of the mandibular molars was measured relative to the cranial floor or within the mandible itself, the mandibular first molar was located more posteriorly on the Class II side of the subdivision malocclusion within a mandible that exhibited no other unusual asymmetry.

Mandibular asymmetry and condylar position in children with unilateral posterior crossbite.

The purpose of this retrospective study was to determine if condylar position in children with functional unilateral crossbites was different from that found in children with Class I noncrossbite malocclusions and if there was a change in condylar position after correction of the crossbite by palatal expansion. Mandibular asymmetry in children with functional unilateral posterior crossbite was also compared to that of a Class I noncrossbite group. Thirty-one children aged 6 to 14 years (mean, 9.3 years; standard deviation, 2.2) with functional unilateral crossbites were compared to 31 children aged 9.5 to 14.1 years (mean, 11.9 years; standard deviation, 1.3) exhibiting Angle Class I noncrossbite malocclusions. Pretreatment submentovertex radiographs were used to study mandibular skeletal, dental, and positional asymmetries with reference to cranial floor and mandibular coordinate systems. In addition, the anterior, superior, and posterior joint spaces were measured to determine differences between the groups with the use of pretreatment and posttreatment horizontally corrected tomograms of the temporomandibular joints. Finally, the distances of the mesiobuccal cusp of the upper first molar relative to the buccal groove of the lower first molar were measured in both groups before treatment. Univariate analyses revealed that the mandibles of children in the functional unilateral posterior crossbite group exhibited asymmetry in both anteroposterior and transverse dimensions when compared with the Class I noncrossbite group (P <. 05). These asymmetries were the result of a functional deviation of the mandible that was present in all subjects in the crossbite group. This deviation was manifested occlusally by a Class II subdivision on the crossbite side as indicated from the study model analysis (P <.05). Examination of condylar position as evidenced by horizontally corrected tomograms demonstrated a large standard deviation, resulting in an inability to detect any significant differences within or between groups at both T1 and T2 (P >.05). This study raised the question of the appropriateness of measuring joint spaces for routine diagnostic purposes.

Resolution of mandibular arch crowding in growing patients with Class I malocclusions treated nonextraction

The purpose of this study was to determine the manner in which mandibular arch crowding was resolved in Class I growing patients who were treated nonextraction. A retrospective study was completed with 30 patients from a postgraduate orthodontic clinic, treated with a variety of treatment modalities. Eight study models and six cephalometric parameters were examined before treatment and at the end of active treatment (posttreatment). The results showed that statistically significant increases in arch width occurred at the canine (0.9 mm), first premolar (1.6 mm), second premolar (1.8 mm), and first molar (1.2 mm). The incisors were advanced an average of 2.1 mm and proclined 6.1 degrees. The molars showed no anteroposterior movement. Arch perimeter increased 2.3 mm and arch depth increased 1.6 mm. Multiple linear regression analysis revealed that 52% of the variance in crowding resolution was accounted for by an increase in arch perimeter. It was concluded that the resolution of crowding, in this group of patients with Class I malocclusions, was achieved by generalized expansion of the buccal segments, along with advancement of the lower incisors. In some cases, these changes may be consistent with treatment objectives; in others, they may be undesirable. It is therefore important for practitioners to carefully evaluate treatment outcome irrespective of the treatment modality, to determine whether treatment objectives are being met.

The risk of orthodontic treatment for producing temporomandibular mandibular disorders: A literature overview

T h e benefits of orthodontic treatment in the management of temporomandibular disorders (TMD) is questionable, since the occlusion is considered as having a limited role in the cause of TMD as recently stated by Seligman and Pullinger t after an extensive review of the literature. However, the potential detrimental effects of orthodontic treatment has captured the attention of the orthodontic community over the last decade. Several studies have been published previously addressing the question of a possible functional risk or benefit of orthodontic treatment on the temporomandibular joint (TMJ) and masticatory musculature. The purpose of this paper is to provide a somewhat detailed review of those studies in which samples of orthodontically treated patients have been evaluated. In addition to the six studies referenced by Reynders 2 in a recent review of the literature from 1966 to 1988, eight more studies will be reviewed to provide the reader with specific information as background with which to compare future studies (Table I).

Effectiveness and duration of orthodontic treatment in adults and adolescents

The purpose of this investigation was to compare the effectiveness and duration of orthodontic treatment in adults and adolescents with a valid and reliable occlusal index. Another aim was to evaluate variables that may influence the effectiveness and duration of orthodontic treatment in general. Pretreatment and posttreatment study models were scored using the Peer Assessment Rating Index. The difference in scores between pretreatment and posttreatment stages reflects the degree of improvement and therefore the effectiveness of treatment. Variables that reflect patient compliance were recorded from written treatment records from three private orthodontic practices. The sample consisted of 32 adults (mean age, 31.3 years) and 40 adolescents (mean age, 12.9 years), all of whom had four premolars extracted as part of the treatment strategy. The results indicated that there were no statistically significant differences (P > .05) between adults and adolescents regarding treatment effectiveness (occlusal improvement) and treatment duration. Multiple regression techniques revealed that the number of broken appointments and appliance repairs explained 46% of the variability in orthodontic treatment duration and 24% of the variability in treatment effectiveness. Furthermore, orthodontic treatment of the buccal occlusion and overjet explained 46% of the variability in treatment duration.